Problem Statement

Take a string and repeat it some number of times.
Example: repeat("ha", 5)   =>   "hahahahaha" If there is a simpler/more efficient way to repeat a single “character” (i.e. creating a string filled with a certain character), you might want to show that as well (i.e. repeat-char("*", 5) => "*****").

Let's start with the solution:

#lang racket
;; fast
(define (string-repeat n str)
  (string-append* (make-list n str)))
(string-repeat 5 "ha") ; => "hahahahaha"

(make-string 5 #\*) => "*****"